The invention relates to cutting or severing apparatus in general, and more particularly to improvements in apparatus for cutting stacks of sheets or discrete sheets of paper or the like. Still more particularly, the invention relates to improvements in cutting or severing apparatus of the type having one or more severing units each of which includes a mobile knife and a stationary knife or counterknife.
The position of the cutting edge of one knife relative to the other knife of a severing unit for paper sheets or the like must be adjusted from time to time. As a rule, the adjusting mechanism includes displacing elements in the form of bolts or wedges which are installed in a holder for the blade of the knife and are movable to thereby change the position of the cutting edge of the blade. Reference may be had, for example, to U.S. Pat. No. 4,392,402 granted Jul. 12, 1983 to Rann. This patent describes an apparatus for severing running webs of paper or the like. The apparatus has a set of counterknives which orbit at one side of the path for the running web and a set of knives with adjustable blades which orbit at the other side of the path to cooperate with the orbiting counterknives in order to sever the running web transversely of the direction of longitudinal movement of the web. The adjustable blades are mounted on a common rotary holder and their positions relative to the common holder (and hence relative to the associated counterknives) can be changed by wedges which are accessible at the periphery of the common holder.
The just described apparatus is quite satisfactory for the severing of a single running web or of several overlapping running webs because the adjusting wedges are accessible at the periphery of the rotating holder for the knife blades. However, the situation is different if several cutting or severing units are placed side-by-side in close proximity to each other, e.g., to simultaneously sever a single sheet or several overlapping sheets of paper or the like. Adjusting mechanisms for the blades of such closely adjacent severing units are not readily accessible so that each unit wherein the blade necessitates adjustment must be detached from the reciprocating mechanism for the mobile knives of the severing units before the adjusting mechanism for the blade is accessible for manipulation in order to change the position of the cutting edge of the blade with reference to the blade holder. All this takes up much time and can cause considerable losses in the output of a production line for steno pads, exercise pads and/or other stationery products.
Cutting apparatus with several parallel severing units are often utilized in production lines wherein stacks of relatively large paper sheets are severed at a plurality of locations to convert the stacks into discrete pads or like stationery products wherein the sheets are held together by helical binders, by strips of adhesive or in any other suitable way. Dismantling of the severing apparatus for the sole purpose of adjusting the cutting edge of the blade in a single severing unit would entail huge losses in the output of such production lines.